Paving joint mortars

ABSTRACT

Polymer powders redispersible in water in paving joint mortars, the paving jointing mortar having approximately 0.5% by weight or more, based on the paving joint dry mortar, of one or more mineral binders, as well as one or more additives and, if necessary, further components. The paving joint mortar can be introduced into a joint in powder form and subsequently watered, or the paving joint mortar can be mixed with water before introduction into the joint and added to the joint in paste form.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of European Application No. 06 015384.8, filed 24 Jul. 2006.

The present invention relates to paving joint mortars. Moreparticularly, the present invention relates to polymer powdersredispersible in water and their use in paving jointing mortarscontaining mineral binders.

Paving joint mortar is understood by one skilled in the art as jointmortar commonly used in the open air for jointing paving stones, naturalstones and natural stone slabs, concrete stone slabs and concrete pavingstones, mosaic flooring and mosaic paving, composite stone, naturalstone paving, paving flag, large stone paving and small stone paving,cobble stone paving, erratic block paving, wooden paving and decking aswell as cement clinker paving, among others. Such paving is used, forexample, for pedestrian areas, roads, foot paths, cycling paths, accessways, gutters, and parking areas, as well as in garden architecture. Thepaving is introduced predominantly by garden designers and road buildersby way of a so-called “loose construction method”, which is the mostcommonly used and one of the oldest methods of construction for suchsurfacing. In this method, the stones to be laid are placed onto a loosebed of chippings, sand or granules and subsequently jointed. The jointwidth may range, for example, from a few millimeters to a fewcentimeters. This type of construction responds to static or dynamicstresses by elastic deformation. Thermal impact is eliminated byunhindered deformation without stresses occurring. The paving coverremains basically permeable to water. It is generally perceived as adisadvantage in that the jointing material can be washed out from thejoint or sucked up, for example, by sweeping machines. As a consequence,the stones may lose their hold. In addition, weeds can grow in thesejoints in the case of sparse traffic, something that is often perceivedas undesirable, particularly in the case of natural stone surfaces.

Sand is the most commonly used jointing material, and can be introducedin powder form, for example, by means of a broom. It adapts withoutproblem to the movement of the slabs and to the subgrade. An embodimentbased on this is described in EP 1 484 295 A1, wherein a small portionof fibrous substances is mixed with the sand. Still, in this type ofconstruction the above mentioned disadvantages of the state of the artpersist.

In DE 44 21 970 A1 a jointing material and its use for jointing naturalstone or synthetic stone paving is described. The jointing materialincludes a mixture of quartz sand with an addition of silica dust and aliquid polymer binder. The binder is typically composed of a mixture ofpolybutadiene, boiled linseed oil and isoparaffinic hydrocarbonmixtures. This mixture is swept with a broom as a soil-moist mass intothe dry joints, compacted with a vibrating plate, and subsequentlyscraped off with a rubber scraper. This type of jointing material isconsequently time-consuming to produce and apply. Moreover, such systemscan have low strength levels.

DE 102 49 636 A1 describes a similar approach. Here, functionalisedpolymer powders redispersible in water are mixed with jointing sand. Thepolymer powders self-crosslink in acidic or slightly alkaline medium,resulting in permanent compaction of the joint filling compound. Waterpermeability of the moulded body produced is improved by using thecrosslinking polymer powder. The 636 publication does not describe howthe jointing sand and the polymer powder are mixed and introduced intothe joints. Strengths, such as tensile strength in bending andcompressive strength, are not indicated. Conventional, non-crosslinkingpolymer powders cannot be used. Moreover, required conditions such asthe pH-range must be accurately maintained in order to guaranteecross-linking.

In another approach, sand is mixed with approximately 20 to 40% byweight of cement and other additives, for example, cellulose fibers, inorder to increase durability and strength. As a result, the pavingjoints become more durable and washable. Also, nothing will grow inthem. As a result of the high rigidity of the joints, such joint fillingmaterials are suitable only for a ‘bound’ method of construction wherepaving stones are laid onto a rigid subgrade such as a concrete slab.This subgrade or support layer underneath the paving must be produced ina manner particularly resistant to deformation using appropriatematerials and requires accurate planning. Still, stresses frequentlyoccur, which may be due to changes in temperature. This frequentlycauses cracks and joints to loosen, resulting in the stones becomingdetached. For this reason, two-component (2K) jointing mortars based onresin are very frequently used for this bound method of construction.These mortars do not respond in an elastic manner to stress, but ratherin a rigid manner comparable to concrete surfaces. However, such systemsare expensive, complicated to apply, and cannot be used for a non-boundmethod of construction.

JP 2285103 describes the use of silica sand and rubber powder asaggregates, a styrene acrylate copolymer dispersion, and Portland cementas binders. The joint filling material is first sprayed and then thejoints are filled with it. After filling, the surface then has to besprayed with a cleaning agent and cleaned with a polishing machine. Thisjointing material consists of two components and therefore needs to bethoroughly mixed by stirring, meaning additional effort is required.Moreover, the subsequent cleaning process is time consuming to execute.

In order to produce a single component mortar that has been improvedwith a polymer, polyvinyl alcohol in powder form can be added to apaving joint dry mortar with approximately 2 to 7% by weight of cement.The paving joint dry mortar scattered into the joint is then wetted withwater from the outside. Although this is simple to handle, the watercannot penetrate into the deeper layers due to the polyvinyl alcoholswelling rapidly on contact with water, resulting in an uneven andunsatisfactory introduction of water into the mortar. Moreover,polyvinyl alcohol provides a greasy consistency and tends to easily formfoam. During continued contact with water, polyvinyl alcohol is alsowashed out over time, which may result in embrittlement of the pavingjoint.

In one embodiment, the present invention provides a single componentpaving jointing dry mortar in powder form for the loose method ofconstruction. The mortar is simple to handle and apply. The appliedmortar exhibits an increased durability, certain flexibility, as well asa corresponding compressive and tensile strength in bending. Moreover,the paving joint mortar possesses good flank adhesion, that is, a goodadhesion to the paving stone that is resistant to mechanical stressessuch as those caused by sweeping machines, high pressure cleaningmachines, and/or driving rain. It also provides for easy removal bywashing of contamination from paving jointing mortar residues on thepaving stones, thereby simplifying subsequent cleaning considerably.

In another embodiment the present invention provides paving jointmortars having polymer powders redispersible in water. The paving jointmortar can also having one or more mineral binders in an amount of about0.5% by weight or more, based on the desired paving jointing dry mortar,as well as one or more additives and, optionally, further components.The paving joint mortar can be introduced into a joint in powder formand subsequently watered, or it can be mixed with water beforeintroduction and added to the joint in paste form.

In one aspect, paving joint mortars having the polymer powderredispersible in water can have one or more mineral binders in about 0.5to about 30% by weight. In another aspect, the one or more mineralbinders are present in an amount of about 1.0 to about 20% by weight. Ineven another aspect, the binders are present in an amount of about 1 toabout 10% by weight. In another aspect the binders are present in anamount of about 1 to about 5% by weight. In one embodiment, the amountof additives in the paving joint mortars is about 30 to about 99% byweight. In another aspect, the amount of additives is about 50 to about98% by weight. In even another aspect, the amount of additives is about60 to about 95% by weight. In a further aspect, the amount of additivesis about 70 to 90% by weight, In one embodiment, the amount of polymerpowder redispersible in water present in the paving joint mortar isabout 0.5 to about 20% by weight, In another aspect, the amount ofpolymer powder is present in an amount of about 1.0 to about 15% byweight. In a further aspect, the amount of polymer powder is present inan amount of about 0.5 to about 10% by weight. In another aspect, theamount of polymer powder is present in an amount of about 2 to about 7%by weight. Other optional components can be present in the paving jointmortar in an amount of about 0 to about 25% by weight. In one aspect,other components are present in an amount of about 0 to about 20% byweight, based on the paving jointing dry mortar, respectively.

Suitable mineral binders include at least (a) hydraulically bindingbinders such as cement, (b) latent hydraulic binders such as acidicblast-furnace slag, pozzolans and/or metakaolin, and/or (c)non-hydraulic binders that react under the influence of air and water,such as calcium hydroxide and/or calcium oxide.

In one embodiment, cement such as Portland cement (e.g., according to EN196 CEM I, II, III, IV and V), calcium sulfate in the form ofα-hemihydrate and/or β-hemihydrate and/or anhydrite and/or alumina meltcement can be the hydraulically binding binder. Pozzolans such asmetakaolin, calcium metasilicate and/or volcanic slag, volcanic tuff,trass, fly ash, blast furnace slag and/or silica dust can also be usedas a latent hydraulic binder, which, together with a source of calciumsuch as calcium hydroxide and/or cement, reacts hydraulically. Lime inthe form of calcium hydroxide and/or calcium oxide, for example, can beused as non-hydraulic binder reacting under the influence of air andwater. In one embodiment, the systems are based on Portland cement or amixture of Portland cement, alumina melt cement and calcium sulfate,where latent hydraulic and/or non-hydraulic binder can optionally beadded to either system.

Examples of suitable additives (sometimes also referred to as fillers)include quartzitic and/or carbonaceous sands and/or meals such as quartzsand and/or ground limestone, carbonates, silicates, chalk, layersilicates and/or precipitated silicic acids. In addition, light weightfillers such as hollow microspheres of glass, polymers such aspolystyrene spheres, aluminosilicates, silicon oxide, aluminium siliconoxide, calcium silicate hydrate, aluminium silicate, magnesium silicate,aluminium silicate hydrate, calcium aluminium silicate, calcium silicatehydrate, silicon dioxide and/or aluminium iron magnesium silicate butalso clays such as bentonite can be used. It is also possible for thefillers and/or light weight fillers to possess a natural or artificiallyproduced color.

Polymer powders redispersible in water according to the invention cancontain at least one polymer based on vinyl acetate, ethylene vinylacetate, ethylene vinyl acetate vinyl versatate, ethylene vinyl acetatevinyl chloride, ethylene vinyl chloride, vinyl acetate vinyl versatate,(meth)acrylate, ethylene vinyl acetate(meth)acrylate, vinyl acetatevinyl versatate(meth)acrylate, vinyl acetate maleic acid and vinylacetate maleic acid ester, vinyl acetate vinyl versatate maleic acid andvinyl acetate vinyl versatate maleic acid ester, vinylacetate(meth)acrylate maleic acid and vinyl acetate (meth)acrylatemaleic acid ester, styrene acrylate and/or styrene butadiene, whereinvinyl versatate is a C₄- to C₁₂-vinyl ester. The polymer powders canalso contain about 0 to about 50% by weight of additional monomers suchas monomers with functional groups. In another aspect, the polymers cancontain about 0 to about 30% by weight of additional monomers. In evenanother aspect, the polymers can contain about 0 to about 10% by weightof additional monomers.

Polymer powders redispersible in water according to the invention can bebased on one or several polymers. These polymers can be produced, forexample, by emulsion polymerisation, suspension polymerisation,microemulsion polymerisation and/or inverse emulsion polymerisation. Ifnecessary, the polymers can also exhibit a heterogeneous morphologyobtained by selecting the monomer and the production process. Subsequentdrying takes place, for example, by spray drying, freeze drying, fluidbed drying, roller drying and/or rapid drying. In one embodiment thepolymer powders are produced by emulsion polymerisation and spraydrying.

Examples of suitable classes of monomers for producing these polymersinclude linear or branched C₁- to C₂₀-vinyl ester, ethylene, propylene,vinyl chloride, (meth)acrylic acid and their linear or branched C₁- toC₂₀-alkyl esters, (meth)acrylamide and (meth)acrylamide withN-substituted linear or branched C₁- to C₂₀-alkyl groups, acrylonitrile,styrene, styrene derivatives and/or dienes such as 1,3-butadiene. In oneembodiment, the vinyl esters are linear or branched C₁- to C₁₂-vinylesters such as vinyl acetate, vinyl stearate, vinyl formate, vinylpropionate, vinyl butyrate, vinyl pivalate, vinyl laurate, vinyl-2-ethylhexanoate, 1-methyl vinyl acetate and/or C₉-, C₁₀- and/or C₁₁-vinylversatate, vinyl pyrrolidone, N-vinyl formamide, N-vinyl acetamide, aswell as vinyl esters of benzoic acid and p-tert.-butyl benzoic acid. Inanother embodiment, the vinyl esters are vinyl acetate, vinyl laurateand/or vinyl versatate. Examples of C₁- to C₁₂-alkyl groups of(meth)acrylic acid esters and N-substituted (meth)acrylamides includemethyl groups, ethyl groups, propyl groups, n-butyl groups, i-butylgroups, tert.-butyl groups, hexyl groups, cyclohexyl groups, 2-ethylhexyl groups, lauryl groups, stearyl groups, norbornyl groups,polyalkylene oxide groups and/or polyalkylene glycol groups. In oneembodiment, the alkyl groups are methyl groups, butyl groups, and/or2-ethyl hexyl groups. In another embodiment, the alkyl groups are methylmethacrylate, n-butyl acrylate, tert.-butyl methacrylate and/or 2-ethylhexyl methacrylate.

Additional monomers such as monomers with functional groups can beincorporated by polymerization. For example, it is possible tocopolymerize maleic anhydride, unsaturated dicarboxylic acids and theirbranched or linear C₁- to C₂₀-esters, such as itaconic acid, maleic acidand/or fumaric acid as well as their esters, multiply ethylenicallyunsaturated copolymers such as e.g. divinyl adipate, diallyl maleate,allyl methacrylate or triallyl cyanurate, divinyl benzene, butanediol-1,4-dimethacrylate, triethylene glycol dimethacrylate, hexane dioldiacrylate, functional vinyl monomers and/or (meth)acrylate monomerscontaining alcoxy silane groups, glycidyl groups, epihalohydrin groups,carboxyl groups, amine groups, hydroxyl groups, ammonium groups and/orsulfonic acid groups. In one aspect the functional monomers can behydroxyl propyl(meth)acrylate, N-methylol allyl carbamate, methylacrylamidoglycolic acid methyl ester, N-methylol(meth)acrylamide, vinylsulfonic acid, acrylamido glycolic acid, glycidyl(meth)acrylate,2-acrylamido-2-methyl propane sulfonic acid, (meth)acryloxypropyltri(alkoxy)silane, vinyl trialkoxysilane, vinyl methyl dialkoxysilanes;methoxy groups, ethoxy groups and/or iso-propoxy groups being used asalkoxy groups; acetyl acetoxyethyl(meth)acrylate, diacetone acrylamide,acrylamido glycolic acid, methyl acrylamido glycolic acid methyl ester,alkyl ether, N-methylol(meth)acrylamide, N-methylol allyl carbamate,esters of N-methylol(meth)acrylamide and of N-methylol allyl carbamate,N-[3-(dimethyl amino)propyl]methacrylamide, N-[3-(dimethylamino)ethyl]meth-acrylamide, N-[3-(trimethylammonium)propyl]methacrylamide chloride and/orN,N-[3-chloro-2-hydroxypropyl)-3-dimethyl ammoniumpropyl](meth)acrylamide chloride. In one aspect the proportion of thesecomonomers is approximately 0 to 30% by weight. In another aspect, it isapproximately 0 to 20% by weight. In even another aspect it isapproximately 0.1 to 10% by weight, based on the total proportion ofmonomer. Care should be taken to ensure that the proportion of freecarboxyl groups is not higher than approximately 10% by weight; inanother aspect not higher than approximately 5% by weight; and in evenanother aspect not higher than approximately 3% by weight.

Choice of initiator system used for polymerisation is not restricted.Thus, all known initiator systems can be used.

In one embodiment the glass transition temperature (“T_(g)”) of theemulsion polymer is within approximately −60° C. to 80° C. In anotherembodiment the temperature is approximately −30° C. to 50° C. In evenanother embodiment the temperature is approximately −20° C. to 40° C.

The glass transition temperature T_(g) of the copolymers produced andconsequently the emulsion polymers can be calculated empirically as wellas determined by experiments from the monomers used. Using the Foxequation (T. G. Fox, Bull. Am. Phy. Soc. (serli) 1, p. 123 (1956) andULLMANNS ENZYKLOPÄDIE DER TECHNISCHEN CHEMIE, Vol. 19, 4^(th) Ed.,Verlag Chemie, Weinheim, 1980, pp. 17-18), they can be calculatedempirically: 1/T_(g)=x_(A)/T_(gA)+x_(B)/T_(gB)+ . . . +x_(n)/T_(gn),with x_(A) , x_(B) . . . the mass fractures of the monomers A, B, . . .used (in % by weight) and T_(gA), T_(gB) . . . the glass transitiontemperatures T_(g) in Kelvin of the homopolymers of A, B, . . .concerned. These are listed in, for example, ULLMANNS ENZYKLOPÄDIE DERTECHNISCHEN CHEMIE, VCH, Weinheim, Vol. A21 (1992), p. 169. Anotherpossibility for determining the glass transition temperatures T_(g) ofthe copolymers is experimental determination, for example, by DSC, theaverage temperature being used (midpoint temperature according to ASTMD3418-82).

Emulsion, suspension, microemulsion and/or inverse emulsion polymersproduced can be stabilised with one or more higher molecular compounds,such as one or more protective colloids. The quantity of stabilizingsystems used is approximately 1 to 30% by weight. In another aspect theamount used is approximately 3 to 15% by weight, based on the proportionof monomer used.

Typical water-soluble organic polymeric protective colloids includehigher molecular compounds. These include natural compounds such aspolysaccharides, including chemically modified ones, synthetic highermolecular oligomers and polymers having no or only a slight ioniccharacter, and/or polymers produced with monomers having an at leastpartially anionic character and, e.g., by radical polymerisation in situin the aqueous medium. It is also possible for only one stabilisingsystem to be used or for different stabilising systems to be combined.

Useful polysaccharides and their derivatives include polysaccharides andpolysaccharide ethers soluble in cold water such as cellulose ether,starch ether (amylose and/or amylopectin and/or their derivatives), guarether and/or dextrins. It is also possible to use syntheticpolysaccharides such as anionic, non-ionic or cationicheteropolysaccharides such as xanthan gum or wellan gum. Thepolysaccharides can, but need not, be chemically modified, e.g., withcarboxymethyl groups, carboxyethyl groups, hydroxyethyl groups,hydroxypropyl groups, methyl groups, ethyl groups, propyl groups and/orlong-chain alkyl groups. Further natural stabilising systems consist ofalginates, peptides and/or proteins such as gelatin, casein and/or soyprotein. Examples include dextrins, starch, starch ether, casein, soyprotein, hydroxyl alkyl cellulose and/or alkyl hydroxyalkyl cellulose.

Synthetic stabilising systems include one or several polyvinylpyrrolidones and/or polyvinyl acetals having molecular weights ofapproximately 2000 to 400,000; fully or partially saponified and/ormodified fully or partially saponified polyvinyl alcohols with a degreeof hydrolysis of approximately 70 to 100 mole %, or in another aspectapproximately 80 to 98 mole %, and a viscosity according to Höppler in a4% aqueous solution of about 1 to 50 mPas, or in another aspectapproximately 3 to 40 mPas (measured according to DIN 53015 at 20° C.);as well as melamine formaldehyde sulfonates, naphthalene formaldehydesulfonates, block copolymers of propylene oxide and ethylene oxide,styrene-maleic acid copolymers and/or vinyl ether-maleic acidcopolymers. Higher molecular oligomers may include non-ionic, anionic,cationic and/or amphoteric emulsifiers such as alkyl sulfonates, alkylaryl sulfonates, alkyl sulfates, sulfates of hydroxyl alkanols, alkyldisulfonates and alkyl aryl disulfonates, sulfonic fatty acids, sulfatesand phosphates of polyethoxylated alkanols and alkyl phenols, as well asesters of sulfosuccinic acid, quaternary alkyl ammonium salts,quaternary alkyl phosphonium salts, polyaddition products such aspolyalkoxylates, e.g., adducts of 5 to 50 mole ethylene oxide and/orpropylene oxide per mole of linear and/or branched C₆- to C₂₂-alkanols,alkyl phenols, higher fatty acids, higher fatty acid amines, primaryand/or secondary higher alkyl amines. The alkyl group can be a linearand/or branched C₆- to C₂₂- alkyl group in each case. Syntheticstabilising systems include partially saponified and/or modifiedpolyvinyl alcohols, it being possible for one or several polyvinylalcohols to be used together, if necessary with small quantities ofsuitable emulsifiers. Synthetic stabilising systems further includemodified and/or non-modified polyvinyl alcohols with a degree ofhydrolysis of 80 to 98 mole % and a viscosity according to Höppler as 4%aqueous solution of 1 to 50 mPas and/or polyvinyl pyrrolidone.

According to a specific embodiment, an ionic polymer obtained by radical(co)polymerisation of olefinic monomers in water wherein at least partof the olefinic monomers containing an ionic group is used as thestabilising system. Such systems are typically obtained in situ, itbeing possible for (meth)acrylic acid, monomers with sulfonic acidgroups and/or cationic monomers, for example, to be used as monomerswith an ionic group, such as described in EP-A 1098916 and EP-A 1109838.

Moreover, polymers containing carboxyl group based on monocarboxylicand/or dicarboxylic acids or their anhydrides, for example, polyacrylicacids, can be used as stabilising systems. However, care should be takento ensure that the quantity of such a stabilising system and/or thequantity of polymer powder re-dispersible in water used is not chosentoo large so as not to influence the hydration of the mineral bindersand its processing in an excessively negative manner.

A film forming aid and/or a coalescing agent can also be added to thepolymer powders redispersible in water. The amount can be approximately0 to 5% by weight, or in another aspect, approximately 0 to 2% byweight, based on the copolymer content.

Polymer powders redispersible in water include those with a lowproportion of organic volatile components (VOC), such as thosepossessing a boiling point of less than 250° C. at normal pressure.These include, for example, non-reacted monomers and non-polymerisablecontaminants contained in the monomers and by-products of thepolymerisation. VOC content of the polymer powders redispersible inwater amounts to less than approximately 5000 ppm, in another aspectless than 2000 ppm, in even another aspect less than 1000 ppm, and inanother aspect less than approximately 500 ppm, based on polymercontent.

Other components such as additives can be added to the polymer powdersredispersible in water, with their addition occurring before, duringand/or after drying. The types of these components used are numerous.Liquid components can be added before or during drying, but can also besprayed onto the powder subsequently. Components in powder form can beadded during or after spray drying, but can also be added duringdispersion mixing before the drying step.

One embodiment includes the addition of at least one further organiccomponent with functional groups. This can be part of the polymer powderre-dispersible in water and/or can be mixed with the paving joint drymortar as a separate component. If this component is liquid, it can beadded to the polymer powder redispersible in water during its productionor transformed into powder form. When used in powder form, it can bemixed with the polymer powder redispersible in water and/or the pavingjointing dry mortar. Useful organic components with functional groupsreact in an alkaline medium either with itself and/or other compounds.Examples of such compounds include crosslinking agents such as epoxides,epoxy resins, oligoamines and/or polyamines, bifunctional maskedaldehydes with at least 3 carbon atoms, silanes, siloxanes, isocyanateswhich can be used together with hydroxy compounds such as polyols, ifnecessary, boric acid and/or borax and/or compounds with carbodiimidegroups, carboxyl groups and/or epichlorohydrin groups.

Functional groups of these organic components and of the(co-)polymerisable monomers with functional groups include silane groupssuch as alkoxy silane groups, glycidyl groups, epihalohydrin groups,N-methylol groups, carboxyl groups, amine groups, hydroxyl groups,ammonium groups, ketone groups, acid anhydride groups, acetoacetonategroups, sulfonic acid groups, amide groups, amidine groups, iminegroups, ester groups, carboxyl groups, carbonyl groups, aldehyde groups,sulfate groups, sulfonate groups and/or thiol groups. In one aspect thefunctional groups are silane groups, epoxy groups, epihalohydrin groupsand/or amine groups.

The paving joint mortar can also contain further components in typicalquantities.

It is advantageous if they are present in powder form. If they are bynature liquid, they can be adsorbed onto a matrix or embedded in amatrix in order to be able to handle them in powder form. There are noessential limitations regarding the type of these further components.Non-limiting examples of such further components are colour pigments,cellulose fibers, water-soluble polymers, in particular fully orpartially saponified and, if necessary, modified polyvinyl alcohols,polyvinyl pyrrolidones, polyalkylene oxides and polyalkylene glycols,the alkylene group typically being a C₂- and/or C₃-group, which includesalso block copolymers, thickening agents, water retention agents, alkylhydroxyalkyl ethers and/or alkyl hydroxyalkyl polysaccharide ethers suchas such as cellulose ether, starch ether and/or guar ether, the alkylgroup and hydroxyalkyl group typically being a C₁- to C₄-group,synthetic polysaccharides such as anionic, non-ionic or cationicheteropolysaccharides, in particular xanthan gum or wellan gum, wettingagents, dispersing agents, cement liquefiers, polycarboxylates,polycarboxylate ethers, polyacrylamides, hydrophobing agents such assilanes, silane esters, siloxanes, silicones, fatty acids and/or fattyacid esters, air pocket formers, rubber powders, biocides, herbicides,fungicides, defoaming agents, fragrances for keeping animals away,additives for reducing sedimentation, segregation and/or efflorescencesuch as compounds based on natural resins, in particular rosin and/orits derivatives, setting and solidification accelerators, settingretarders and/or powders which have an alkaline reaction with, watersuch as oxides and/or hydroxides of alkali salts and/or alkaline earthsalts such as calcium hydroxide, calcium oxide, sodium hydroxide and/orpotassium hydroxide and/or aluminium hydroxide.

In principle, all organosilicone compounds can be used as silanes,silane esters, silicones and/or siloxanes. However, it is advantageous,though not compelling for the boiling point of the organosiliconcompound used not to be too low at normal pressure, for example,approximately 100° C. and more. The organosilicon compounds may besoluble, insoluble or only partially soluble in water. Useful compoundscan have no or only limited solubility in water. These may consist ofsilicic acid esters with the formula Si(OR')₄, organoxysilanes with theformula Si(OR′)_(4-n) where n=1 to 3, polysilanes with the formulaR₃Si(SiR₂)_(n)SiR₃ where n=0 to 500 or in another aspect n=0 to 8,disiloxanes, oligosiloxanes and polysiloxanes of units with the generalformula R_(c)H_(d)Si(OR′)_(e))OH)_(f)O_((4-c-d-e-f)/2) where c=0 to 3,d=0 to 2, e=0 to 3, f=0 to 3 and the sum of c+d+e+f is a maximum of 3.5per unit, R′ representing identical or different alkyl radicals oralkoxy alkylene radicals with 1 to 4 C-atoms (e.g., methyl or ethyl) andR being identical or different and representing branched or non-branchedalkyl radicals with 1 to 22 C-atoms, cycloalkyl radicals with 3 to 10C-atoms, alkylene radicals with 2 to 4 C-atoms, aryl radicals, aralkylradicals, alkyl aryl radicals with 6 to 18 C-atoms. The above mentionedradical R can be substituted with halogens such as F or Cl, with ethergroups, thioether groups, ester groups, amide groups, nitrile groups,hydroxyl groups, amine groups, carboxyl groups, sulfonic acid groups,carboxylic anhydride groups and carbonyl groups. R can also have themeaning OR′ in the case of polysilanes.

Further components also include polysaccharide ethers such as celluloseether and/or starch ether, hydrophobing agents such as silanes, silaneesters, fatty acids and/or fatty acid esters, agents for reducingefflorescence, for example, those based on natural resins, cellulosefibres, defoaming agents and/or pigments.

The proportion of these additional components may be very small, forexample, for surface-active substances, based on the paving jointing drymortar, and be within the region of approximately 0.01% by weight ormore, in another aspect approximately 0.1% by weight mid more, butshould not typically exceed approximately 2% by weight, in anotheraspect approximately 1% by weight. On the other hand, the proportion ofmixed pigments can be higher, but should be not more than approximately25% by weight, in another aspect not more than approximately 20% byweight, and in even another aspect not more than approximately 15% byweight. The proportion of hydrophobing agents is approximately 0.05 toapproximately 3% by weight, in another aspect approximately 0.1 toapproximately 2% by weight and in even another aspect approximately 0.2to approximately 1% by weight. The content of the other components isbetween approximately 1% by weight and approximately 15% by weight, inanother aspect between approximately 2 and approximately 10% by weight,based on the paving jointing dry mortar.

As a rule, it is beneficial for the user if the paving jointing mortaris scattered as paving jointing dry mortar into the empty joints orswept into them with a broom, and water then subsequently added, forexample, over the surface. Such addition of water over the surfacewithout subsequent mixing of the mortar is sufficient to bothre-disperse the polymer powder re-dispersible in water in this compactenvironment and distribute it in the matrix. On setting and drying ofthe paving jointing mortar, a water-insoluble film is then formed. Thisthus increases the cohesion of the set paving jointing mortar.

When introducing water over the surface, suitable methods include thosein which the paving jointing dry mortar scattered or swept in is notdamaged. For example, this can be accomplished with a gentleintroduction of water in the form of a spray mist and/or surfacewatering. The method of water introduction is not restricted in any wayas long as it does not damage the paving jointing mortar introduced.This can be achieved with a lawn sprinkler, a water sprinkler, a gardenhose with or without distributor nozzle and/or a watering can. It isadvantageous to set the duration of watering such that the waterpenetrates through the entire paving jointing dry mortar, providing themortar with sufficient water for hydration down to the subgrade. If toomuch water is added, the excess seeps into the subgrade, usually withoutnegative consequences. If insufficient water is added, only the upperpart of the paving jointing mortar is hydrated. During later watering,either artificially or by rain or dew, further water can then diffusethrough the mortar set at the surface and penetrate into deeper layers.However, it is also possible for the water to pass into the pavingjointing dry mortar through the subgrade, thus causing hydration.

According to a further embodiment, the paving jointing dry mortar isfirst stirred with water and introduced into the joints as stirredmortar. In the case of this variation, however, it is helpful to adjustthe quantity of water in such a way that the stirred mortar receives aneasily processable consistency in order to be introduced into the jointswithout running off.

Paving jointing mortar containing the polymer powder re-dispersible inwater that can be used according to the invention typically exhibits ahigh level of wettability. The polymer powder re-dispersible in waterre-disperses without additional shearing forces and mixing processes andsubsequently forms a water-insoluble film. Thus, polymer powdersre-dispersible in water results in none or only minor disadvantagesvis-à-vis emulsifier-stabilised dispersions with the physical values ofthe set paving jointing mortar, even though these systems havepreviously been thoroughly mixed in order to guarantee a correspondinghomogeneity of the mortar. Nevertheless, the end properties of thepaving jointing mortar are entirely comparable in spite of a muchsimpler introduction and processing.

The invention will be explained in further detail by way of thefollowing examples.

EXAMPLE 1 Production and Watering by Spray Mist of Paving Joint DryMortar Introduced by Scattering

Mortar prisms were produced in order to investigate the introduction byscattering and watering of joints under conditions which are as clearlydefined as possible. From this it was possible to subsequently determinephysical values such as the tensile strength in bending and thecompressive strength.

A paving joint dry mortar was prepared by mixing homogenously in anagitator 5% by weight of Portland cement CEM I 42.5 N, 87% by weight ofquartz sand with a sieve line of 0.063 to 1.5 mm, 3% by weight of acalcium carbonate (Durcal 10) and 5% by weight of a polymer powderredispersible in water. A comparative example was carried out using inplace of the polymer powder a partially saponified polyvinyl alcoholwith a degree of hydrolysis of 88 mole % and a viscosity of 4mPas(according to Höppler as 4% aqueous solution, measured according to DIN53015 at 20° C.) (in the following tables referred to as “PVOH”).Another comparative example was carried out entirely without polymerpowder, the omitted polymer quantity being replaced by quartz sand.

500g of the dry mortar produced were then scattered into a 4 cm×4 cm×16cm metal prism mould, the inside wall of the prism mould having beenpainted with mould oil as release agent using a painter's brush. The dryformulation was compacted by manually shaking and tapping for 10seconds. The surface of the dry mortar scattered in was smoothed offwith a trowel.

A spray bottle typically used for spraying plants was used for watering.The water cone formed during spraying was adjusted so that the water wassprayed selectively onto the mortar surface from a distance of 10 cm.The spray duration was 5 to 10 minutes, depending on how well thesurface was wetted and the water was able to penetrate inside. Thenecessary quantity of water was determined by way of a separate testwherein the surface was damaged periodically using a fine spatula andthe depth of water penetration assessed optically until the water hadreached the lowermost layer of the paving jointing mortar.

During watering the following assessments were carried out: (a) wettingof the surface (i.e., how well the water is absorbed by the joint duringthe entire watering process), (b) water saturation (i.e., how much watercan be sprayed continually onto the prism until water floats on thesurface), (c) bubble formation (i.e., whether bubbles rise to thesurface during or immediately after spraying on of the water, which mayhave a negative influence of the surface properties), and (d) cleaningafter contamination (i.e., how simply the prism mould could be cleanedafter releasing the prisms). These assessments provide a good indicationregarding the behavior of the watered paving joint mortar on the surfaceof the paving stones.

18 hours after completion of the introduction of water, the prisms werereleased and stored at 23° C. and a relative atmospheric humidity of 50%(standard climate).

TABLE 1 Table 1 indicates the quantities of water sprayed onto thedifferent paving jointing mortars containing the polymer powdersre-dispersible in water EVA-1, EVA-2 and St/Ac and the comparativesamples PVOH and without polymer powder and assessment of the differentpaving stone joints during watering^(a)). EVA-1 EVA-2 St/Ac PVOH^(c))Without p.p.^(d)) Quantity of water 9 9 9 12  9 (% by weight) Watersaturation (% 7 7 5 6 None by weight) Wetting of surface ExcellentExcellent Average Excellent Excellent Spray duration (min) 5 5 10 8 5Bubble formation None None None Strong None Cleaning after ExcellentExcellent Excellent Smeared Excellent contamination^(b)) ^(a))Thepolymer powders re-dispersible in water EVA-1, EVA-2 and St/Ac consistof different spray-dried dispersions stabilised with polyvinyl alcoholbased on ethylene-vinyl acetate (EVA-1 and EVA-2) copolymers andstyrene-acrylate copolymers (St/Ac). ^(b))“Excellent” means thatcleaning caused no problems whatsoever and the residues were easilyremoved by washing. “Smeared” means that the residual layer could beremoved only after intensive cleaning. ^(c))PVOH represents partiallyhydrolysed polyvinyl alcohol. ^(d))P.P. represents “polymer powder”.

TABLE 2 Table 2 illustrates the results of repeated watering of thepaving joint mortar in the prism mould at intervals of one hour. Fourprisms were produced per composition, one being put aside after eachwatering cycle for removal from the mould after 18 hours and assessed.The percentage indicated below provides details of the proportion ofprisms which formed a compact unit and did not disintegrate. Moreover,the surface of the last prism was assessed after a storage period of 4days for its surface hardness and surface hydrophobicity. Quantity ofwater^(d)) EVA-1 St/Ac PVOH^(c)) Without p.p.^(d)) 1 Watering 3  60% 60% 20%  95% 2 Watering 6  95%  70% 70% 100% 3 Watering 9 100% 100% 75%100% 4 Watering 12 100% 100% 90% 100% Surface hardness^(e)) Hard AverageHard Soft Surface hydrophobicity^(f)) 5 min 30 sec 30 sec 0 sec^(d))Indicated in % by weight. ^(e))The surface hardness was assessed byscratching with a pointed metal rod. ^(f))To assess the surfacehydrophobicity, 1 ml of water was placed drop-wise onto the surfaceusing a pipette and the time was measured by which all the water hadbeen absorbed by the subgrade.

Tables 1 and 2 show, among other things, that paving joint mortar withpartially hydrolysed polyvinyl alcohol exhibits the greatest waterrequirement. In contrast to paving jointing mortars prepared withoutpolymer powder or with polymer powders redispersible in water (EVA-1,EVA-2 and St/Ac), the paving joint mortar with PVOH absorbs a relativelylarge amount of water at its surface, preventing the water from reachingthe underlying layers. Thus, the mineral binder does not set and theorganic binder does not form a film, resulting in a lack of strength ofthese layers.

Even if wetting of the dry mortar is excellent, the unset pavingjointing mortar may exhibit a moderate hydrophobicity as shown by theexample of EVA-1. This contributes to less dirt penetrating into thejoints and being washed away, particularly in the case of an inclinationand/or fairly strong rain.

TABLE 3 Tensile strengths in N/mm² determined at different storageperiods by bending of the mortar prisms obtained, in line withEN13892-2. Storage time in a standard climate EVA-1 EVA-2 St/AcPVOH^(c)) Without p.p.^(d))  1 day 0.07 0.06 0.04 0.22 0.18  3 days 0.560.43 0.51 0.97 0.35  7 days 1.67 0.99 1.50 1.80 0.50 14 days 2.07 1.051.69 —^(g)) 0.45 28 days 2.19 0.99 1.57 —^(g)) 0.40

TABLE 4 Compressive strength in N/mm² determined after different storageperiods by bending of the mortar prisms obtained, in Line withEN13892-2. Storage time in a standard climate EVA-1 EVA-2 St/AcPVOH^(c)) Without p.p.^(d))  1 day 0.20 0.16 0.17 0.16 0.26  3 days 1.240.94 1.00 1.28 0.75  7 days 5.52 2.37 3.18 2.99 1.02 14 days 6.15 2.633.21 —^(g)) 0.93 28 days 5.41 2.44 2.98 —^(g)) 0.77 ^(g))No valuesavailable.

Tensile strength and compressive strength are excellent measures forassessing cohesion of the watered paving jointing mortar. The valuesgiven in Tables 3 and 4 clearly show the additional cohesion achieved byadding polymer powder redispersible in water versus those containingonly mineral binder (indicated by “without polymer powder”). These highvalues are highly surprising since the dry mortar was merely wateredwithout mixing the mortar. Mixing enhances the redispersion of thepolymer powder redispersible in water, guaranteeing good distribution ofthe redispersion achieved. The cohesion achieved is sufficient toprevent damage, for example, in the case of impact or expert cleaningwith sweeping machines or high pressure cleaners. The correspondingearly strength values additionally provide the paving jointing mortarapplied with sufficient protection against driving rain and hail. Thepolymer powder redispersible in water used provides the paving jointmortar also with a good flank adhesion such that the joint does notdetach itself from the paving stone. The low proportion of mineralbinder guarantees the required flexibility needed to survivedeformations of the subgrade without cracking. As a result of thecontrolled optimisation of the types and quantities of hydraulicallybinding binder used and of the polymer powder redispersible in water, itis, moreover, possible to correspondingly optimize flexibility, tensilestrength and compressive strength, as well as tensile bond strength inline with users' requirements without having to change processing.

EXAMPLE 2 Stirring of Paving Stone Joint Mortar with Water BeforeApplication

The paving joint dry mortar produced according to Example 1 is stirredwith water for one minute using a propeller stirrer at 900 rpm, theamount of water adjusted for consistency. During this process, care wastaken in mixing that the resulting mortar was not too thin but also nottoo highly viscous, and could be introduced into a prism box asdescribed in Example 1 by simply using a trowel. Prior to addition tothe box, the mixed paving joint mortar was allowed to mature for 3minutes and was then stirred once more for 15 seconds. Following theintroduction of the mortar, the surface of the mortar was smoothed offwith a trowel. The storage conditions were handled in a manner analogousto Example 1.

Quantities of water used for adjusting the consistency of the differentsamples of EVA-1, St/Ac and the comparative sample without polymerpowder and tensile strength in bending and compressive strengths afterdifferent storage periods, in N/mm², in line with EN13892-2 areillustrated in Table 5 below.

TABLE 5 Tensile strength in bending Compressive strength (N/mm²) (N/mm²)Storage time in a Without Without standard climate EVA-1 St/Ac p.p.^(d))EVA-1 St/Ac p.p.^(d)) Quantity of water 9.5 9.5 15 9.5 9.5 15 (% byweight) 1 day 0.26 0.30 0.04 0.35 0.49 0.32 3 days 2.13 2.39 0.30 4.114.75 0.54 7 days 3.77 3.58 0.10 9.23 7.36 0.74

Table 5 illustrates that by mixing the paving joint dry mortar withwater prior to introduction into the joints, the physical valuesobtained are slightly higher than by introduction of water over thesurface according to Example 1. Consequently, by using paving joint drymortar according to the present invention, the user has the choice ofchoosing either an extremely simple and convenient type of applicationinvolving dry introduction with subsequent surface watering, or byexternally mixing the paving joint dry mortar with water and subsequentintroduction to obtain even higher physical strength values.

Although the present invention has been described and illustrated indetail, it is to be understood that the same is by way of illustrationand example only, and is not to be taken as a limitation. The spirit andscope of the present invention are to be limited only by the terms ofany claims presented hereafter.

1-14. (canceled)
 15. A method of making a paving joint mortar wherein apaving joint dry mortar is added into a joint in powder form andsubsequently watered to form a paving joint mortar, wherein the pavingjoint mortar comprises: one or more mineral binders in an amount ofabout 0.5% by weight or more, based on total dry weight of the pavingjoint mortar, one or more additives, and one or more polymer powdersredispersible in water.
 16. The method according to claim 15 wherein theone or more mineral binders are present in an amount of approximately0.5 to 30% by weight, the one or more additives are present in an amountof approximately 30 to 99% by weight, and the one or more polymerpowders redispersible in water are present in an amount of approximately0.5 to 20% by weight, all based on total dry weight of the paving jointmortar.
 17. The method according to claim 16 wherein the one or moremineral binders are present in an amount of approximately 1.0 to 20% byweight, the one or more additives are present in an amount ofapproximately 50 to 98% by weight, the one or more polymer powdersredispersible in water are present in an amount of approximately 1.0 to15% by weight, all based on total dry weight of the paving joint mortar.18. The method according to claim 15 wherein the one or more polymerpowders redispersible in water comprises one or more emulsion polymers,suspension polymers, microemulsion polymers and/or inverse emulsionpolymers, each of which have been obtained by drying.
 19. The methodaccording to claim 18 wherein the emulsion polymer, suspension polymer,micro-emulsion polymer and/or inverse emulsion polymer is stabilizedwith one or more high molecular compounds.
 20. The method according toclaim 19 wherein that the emulsion polymer, suspension polymer,micro-emulsion polymer and/or inverse emulsion polymer is stabilizedwith one or more protective colloids and/or with an ionic polymerobtained via radical (co)polymerisation of olefinic monomers in waterwherein at least part of the olefinic monomers contains an ionic group.21. The method according to claim 15 wherein the one or more polymerpowders redispersible in water comprises at least one polymer based onvinyl acetate, ethylene-vinyl acetate, ethylene-vinyl acetate-vinylversatate, ethylene-vinyl acetate-vinyl chloride, ethylene-vinylchloride, vinyl acetate-vinyl versatate, ethylene-vinylacetate(meth)acrylate, vinyl acetate-vinyl versatate(meth)acrylate,(meth)acrylate, styrene-acrylate, and/or styrene butadiene, whereinvinyl versatate is a C₄- to C₁₂-vinyl ester, and wherein the at leastone polymer further comprises 0 to 50% by weight of further monomers,based on total weight of the one or more polymer powders redispersiblein water.
 22. The method according to claim 15 wherein the paving jointmortar further comprises at least one organic component havingfunctional groups, wherein the organic component is in the polymerpowder redispersible in water or in the paving jointing dry mortar. 23.The method according to claim 22 wherein the functional groups of the atleast one organic component further comprise alkoxysilane groups,glycidyl groups, epihalohydrin groups, carboxyl groups, amine groups,hydroxyl groups, ammonium groups, ketone groups, acid anhydride groups,acetoacetonate groups and/or sulfonic acid groups.
 24. The methodaccording to claim 15 wherein the water is added in the form of a spraymist and/or surface watering.
 25. The method according to claim 24wherein the water is added by a lawn sprinkler, water sprinkler, agarden hose with or without distributor nozzle, and/or a watering can.26. The method according to claim 15 wherein the one or more mineralbinders are chosen from a hydraulically binding binder, a latenthydraulic binder, and/or a non-hydraulic binder which reacts under theinfluence of air and water.
 27. The method according to claim 26 whereinthe hydraulically binding binder is at least cement; the latenthydraulic binder is chosen from acidic blast furnace slag, pozzolansand/or metakaolin, and/or a non-hydraulic binder which reacts under theinfluence of air and water; and the non-hydraulic binder is chosen fromcalcium hydroxide and/or calcium oxide.
 28. The method according toclaim 15 wherein the paving joint mortar further comprises componentschosen from colour pigments, cellulose ethers, cellulose fibres,water-soluble polymers, in particular polyvinyl alcohol, thickeningagents, water retention agents, starch ethers, mar ethers, wettingagents, polycarboxylates, polyacrylamides, hydrophobing agents, airpocket formers, biocides, herbicides, fungicides, defoaming agents,fragrances for keeping away animals, additives for reducingefflorescence, sedimentation and/or separation, setting andsolidification accelerators, setting retarders and/or powders which havean alkaline reaction with water.